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IL-1 beta stimulates superoxide and delayed peroxynitrite production by pulmonary vascular smooth muscle cells
1Department of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, Pennsylvania 15261, USA.
Abstract:
Our previous studies have shown that rat pulmonary microvascular smooth muscle cells (RPMSMC) upregulate inducible nitric oxide synthase (iNOS) and produce nitric oxide (NO) when treated with interleukin-1 beta (IL-1 beta). We now report that an additional effect of IL-1 beta stimulation in RPMSMC is an increase in production of superoxide (O2-) that results in the formation of peroxynitrite (ONOO-). IL-1 beta produced a rapid (within 1 h) concentration-dependent increase in O2-, as detected by ferricytochrome c reduction and lucigenin-enhanced chemiluminescence. O2- production was sensitive to quinacrine and diphenyliodinium, suggesting that NADH and NADPH oxidoreductases were responsible. After induction of iNOS and production of iNOS-derived NO, ONOO- was detected by luminol-enhanced chemiluminescence and was found to cause lipid peroxidation and to form nitrotyrosine in the cytoskeleton, detected by immunostaining. Cell viability, however, appeared to be unaffected. IL-1 beta-mediated induction of RPMSMC-derived ONOO- may have significant effects on pulmonary vascular function in sepsis and inflammatory states.
Insights
Interleukin-1 beta stimulates rat pulmonary smooth muscle cells to produce superoxide and peroxynitrite, contributing to vascular dysfunction in inflammatory conditions.
Area of Science:
- Pulmonary vascular research
- Cellular signaling
- Biochemistry
Background:
- Rat pulmonary microvascular smooth muscle cells (RPMSMC) upregulate inducible nitric oxide synthase (iNOS) and produce nitric oxide (NO) upon interleukin-1 beta (IL-1 beta) stimulation.
- Previous studies established the link between IL-1 beta, iNOS, and NO production in RPMSMC.
Purpose of the Study:
- To investigate the additional effects of IL-1 beta stimulation on RPMSMC, specifically focusing on reactive oxygen and nitrogen species production.
- To determine the downstream consequences of IL-1 beta-induced peroxynitrite formation in RPMSMC.
Main Methods:
- Measurement of superoxide (O2-) production using ferricytochrome c reduction and lucigenin-enhanced chemiluminescence.
- Assessment of peroxynitrite (ONOO-) formation via luminol-enhanced chemiluminescence.
- Detection of lipid peroxidation and nitrotyrosine formation using immunostaining.
- Evaluation of cell viability.
Main Results:
- IL-1 beta rapidly and concentration-dependently increased O2- production in RPMSMC, implicating NADH and NADPH oxidoreductases.
- Following iNOS induction and NO production, IL-1 beta stimulation led to ONOO- formation.
- ONOO- caused lipid peroxidation and nitrotyrosine formation in the cytoskeleton.
- Cell viability remained unaffected despite ONOO- production.
Conclusions:
- IL-1 beta induces RPMSMC to produce superoxide and subsequently peroxynitrite.
- This IL-1 beta-mediated peroxynitrite formation may significantly impact pulmonary vascular function during sepsis and inflammation.
- Further research is warranted to elucidate the precise mechanisms and implications for pulmonary vascular diseases.